I'd like to think that any alternatives would have been presented and discussed by the orthodontist.
I also think that, as tough as it is, kids sometimes have to do the right thing and tough it out for a few days to get used to things. If it's too wide, perhaps it can be narrowed a bit to start with, but of course you can't do that until the office opens. If she's in a lot of pain, then I'd call the ortho's emergency line. Did the ortho discuss discomfort and the use of tylenol or other pain reliever? What about sucking on ice chips to reduce inflammation?
But if she's just annoyed, and if her answer to other things tends to me "I don't like this and I want something different, then I'd consider some combination of "Buck up, honey, it will be okay in a few days" and "How about a special treat like a movie?" You've mentioned she is a very picky eater, and I think my answer would depend on whether this is her personality type and something you want to break her of (because we can't always have everything so perfect and trouble-free), vs. true misery which should of course be addressed. How is she with other medical and dental issues (shots, fillings, etc.)? Is she one who never complains, and so this is something out of the ordinary for her to be so upset?
By the time you get in there on Monday to have it removed, it will probably feel much better. And then what will you do? Start over? If she's facing a lifetime of dental issues by not addressing this now, you're not helping her by getting her out of early annoyance now.
You know your kid and we don't, so I'm just posing questions I think you might ask yourself and your orthodontist.